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(No Model.)

J. J. HOGAN.

BOILER.

No. 425,425. Patented Apr. 15, 1890.

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UNITED STATES ATENT FFlCEe JOHN J. HOGAN, OF BROOKLYN, ASSIGNOR TO THE HOGAN ENGINEERING COMPANY, OF NEW YORK, N. Y.

BOILER.

SPECIFICATION formingpart of Letters Patent No. 425,425, dated April 15, 1890.

Application filed July 1, 1889. $erial No. 316,149. (No model.)

To coZZ whom it may concern.-

Be it known that I, JOHN J. HOGAN, a citizen of the United States, residing in the city of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Circulating Boilers, fully described and represented in the fo1lowing specification and the accompanying drawings, forming a part of the same.

The object of this invention is to furnish independent channels for the upward and.

a free circulation of fluid in boilers which are used for generating steam.

The essential feature of the invention is the provision, in connection with a central passage within the boiler for the upward movement of the fluid, of one or more water-conductors isolated wholly or partially from the water and smoke spaces of the boiler, whereby such waterchannels or conductors are protected from the heat of the furnace and from the partial convection of heat from the fluid in the boiler. Such isolated water-channels are therefore exposed to a lower temperature than the actual contents of the boiler, and by their coldness their contents tend to displace the water in the lower part of the boiler, and thus promote an active circulation within the same.

The invention also consists in certain constructive features hereinafter described.

The invention is shown herein applied to an upright tubularboiler, a locomotive-boiler, and a horizontal sectional boiler, and may be applied to boilers of other construction.

Figure 1 is a bottom view or plan of the top section of a boiler constructed in horizontal sections, and Fig. 2 is a central vertical sec-- is connected at its center with the adjacent section or sections by a tubular coupling 2, the area of such connections being adequate to feed the entire heating system which is supplied with hot water by the boiler. The several sections are provided with apertures 41 to permit the passage of the smoke from the fire-box t to the smoke-pipe j, connected with the top space f. v

My improvement is applied to such boiler by forming hollow lugs it upon the outside of such sections and connecting such lugs out side of the smoke-chambers by thimbles Z,

which are adapted to furnish an independent channel for the circulation of the Water in a direction opposite to that through the central connections 15. The thiinbles Z, being isolated from the smoke-chambers and exposed to radiation, are necessarily of a lower tempera- 7o ture than the body of the boiler, and are thus adapted by the lower temperature of the water therein to supply the lower part of the boiler, when required.

7c is the inlet at the bottom of the boiler to receive the return -fluid from the external heating system, and so long as such heating system is in full operation the return-current of water therefrom would amply supply the lower part of the boiler and maintain an active circulation within the same toward the discharge-pipe m at the top of the boiler, which delivers the heated fluid to such system. 4

No additional means of maintaining a free circulation within the boiler would be required to prevent the formation of steam therein so long as the return fiuid corresponded in volume with that discharged by the boiler from the pipe Z; but when the return-pipes from the external system are closed in whole or in part it is very common for the fuel in the fire-box 11 to overheat the Water adjacent to such fire-box, and by driving the water away from the fire-box to cause serious injury thereto.

By the provision of the independent waterchannels formed by the lugs h and thimbles Z the needed circulation within the boiler is fully maintained when the external circulation is cut off, and the formation of steam or the injury of the fire-box is wholly prevented.

When the thimbles Z are intended "only to protect the boiler from overheating by maintaining a circulation within the same at such times as the external circulation is cut off, their combined area does not need to equalthat of the central connections 15. The latter, when provided in a hot-water-circulating boiler, as shown herein, are intended to furnish a free channel for the upward movement of the fluid which enters at the inlet it when warmed by the highly-heated metal immediately over the fire-box.

It will be noticed that the lugs it upon the separate water-sections, and which are connected together by the thimbles Z to form a continuous channel for the descending currents of fluid, are connected directly with the interiors of the several sections, and are thus adapted to furnish a supply of the cooler fluid to each of the water-sections independently. This construction furnishes a great advantage over any water-conductor which might be'connected to the boiler merely at the top and bottom, as it freely supplies each section with the cooler fluid to replace the water that maybe forced therefrom. Without this construction the sections are liable, if a free circulation be not provided, to become overheated and steam generated therein,

which would displace the fluid and expose.

the metal to injury.

The exterior water-conductors, which furnish the cooled channels for the descending currents of fluid, may be connected with the upper and lower parts of the water-space within the boiler at any convenient points; but it is obvious that by providing one or more pairs of such water-conductors and arranging the conductors of each pair at opposite points outside the boiler the circulation .is more perfectly equalized and the cooler fluid is distributed more perfectly to the hot surfaces.

It is obviously undesirable, as well as impossible, to separate the exterior water-conductors from the hotter portions of theboiler in such degree as to render the exterior conductors very cold, the object being merely to disconnect the exterior conductors from the metallic parts of the boiler, so as to prevent the conduction of heat through the metal, the exterior conductors being thus cooled in a sufiicient degree to determine a circulation downward through the same, as desired.

It will be noticed that the external conductors formed by the thimblesl are not sep-v arated from the body of the boiler by any airspace, but that they are exposed to radiation by their formation in the hollow lugs h, proso as to be cooled with certainty to a temperature below the boiler itself.

I have not claimed herein the special construction for the boiler in separate cast-iron sections constructed to practice my present invention, as I have claimed the same in my pending application, Serial No. 316,150, filed of even date herewith.

Having thus set forth my invention, what I claim herein is- 1. In a boiler, the combination, with a central water-passage extended vertically within the boiler for the upward movement of the fluid, of one or more water-conductors exterior to the water-space of the boiler and connected therewith at its upper and lower parts and exposed to a lower temperature than the'contents of said water-space, substantially as herein set forth.

2. In a boiler, the combination, with a central water-passage extended vertically within the boiler for the upward movement of the fluid, of one or more pairs of water-conductors arranged at opposite sides of the boiler exterior to the same and connected with the water-space of the boiler at its upper and lower parts, as and for the purpose set forth.

3. In a boiler comprising a series of watersections separated by intermediate smokechambers, the combination, with a waterpassage extending vertically within-the boiler through the centers of the water-sections, of one or more water-conductors exterior to the water-space of the boiler and connected therewith at its upper and lower parts and 'also'to the intermediate water-sections, substantially as herein set forth.

In testimonywhereof I have hereunto set my hand in the presence of two subscribing witnesses.

JOHN J. HOGAN.

Witnesses:

THos. S. CRANE, HENRY J. MILL R. 

